Possible excited deformed rotational bands in82Ge

Abstract

Excited states of neutron-rich nucleus ${}^{82}$Ge were studied from the spontaneous fission of ${}^{252}$Cf. Eleven new transitions and seven new levels in ${}^{82}$Ge were identified by using $X$(Dy)-$\ensuremath{\gamma}$-$\ensuremath{\gamma}$ and $\ensuremath{\gamma}$-$\ensuremath{\gamma}$-$\ensuremath{\gamma}$ triple coincidences. Possible excited deformed rotational bands are observed, for the first time, in this nuclear region. Coexistence of the spherical ground and deformed excited shapes is proposed in ${}^{82}$Ge. These deformed rotational bands can be formed by two-particle, two-hole excitations with the 0${}^{+}$ pairing energy states of the $\ensuremath{\nu}9/2{[404]}^{\ensuremath{-}2}\ensuremath{\bigotimes}1/2{[431]}^{2}$ configuration across the $N=50$ closed shell.